Brown Marmorated Stink Bug
Hitches Ride to Michigan

Published on June 7, 2011

Brown Marmorated Stink Bug

THE ASIAN LONG-HORNED beetle, Asian gypsy moth, Sirex
noctilio wood wasp and emerald ash borer may possess names that sound like
bad-guy characters in the next X-Men cinematic installment, but these real-world
villains have caused billions of dollars of crop and tree damage over the
course of the past decade — not to mention the overall negative environmental
impact posed by insects invading Michigan from other states and countries.

Add to this list of insect evildoers the Brown Marmorated
stink bug. The name “stink bug” may make readers laugh at first, but there’s
more at stake in Michigan than an insect with a funny name that emits foul
odors when you squash it.

During the winter
months, the bug seeks to escape the cold by taking up residence in households,
but when the weather turns warm and fields, orchards, nurseries and gardens
once again become productive, they turn into destructive eating machines. The
Michigan Department of Agriculture says stink bugs relish fruit trees,
ornamental plants and field crops the same way a certain cartoon cat craves
lasagna.

‘Exceptionally Good Hitchhikers’

Adult stink bugs
grow to an average of 17 millimeters long. The stinkers are shield-shaped and
feature shades of brown coloring on their top and bottom. “They are the typical
‘shield’ shape of other stink bugs, almost as wide as they are long,” said Jennifer
Holton, public information officer for the Michigan Department of Agriculture
and Rural Development.

“(They)
superficially resemble several common species of stink bug native to Michigan,”
Holton added. “Some of these native species are plant-feeding agricultural
pests, while others are considered beneficial because they prey on other
insects,” she said.

“To distinguish
them from other stink bugs, look for lighter bands on the antennae and darker
bands on the membranous, overlapping part at the rear of the front pair of
wings,” Holton said. “They have patches of coppery or bluish-metallic colored
punctures — small rounded depressions — on the head and pronotum[1]. The
name ‘stink bug’ refers to the scent glands located on the dorsal surface of
the abdomen and the underside of the thorax.”

Native to East
Asian countries, the first stink bugs were detected in the United States about
10 years ago, said Holton. She says stink bug specimens were initially
identified in Pennsylvania. They have since spread to “most states on the East
Coast” and Michigan, and their presence also has been discovered in California
and Oregon.

Females lay eggs
throughout their adult lives. The female lays approximately 28 eggs,
totalling around 240 eggs in her lifetime.

According to Dr.
Anne Nielsen, research associate in organic pest management at Michigan State University,
stink bugs more than likely bummed rides on freight ships from American coastal
ports, and made their way to current locations by stowing away on trucks and
cars. “We believe stink bugs came from Asia through such international shipping
ports as Port Elizabeth in New Jersey,” Nielsen said. “From there, they
traveled in shipping containers to Allentown, Pa. They’re exceptionally good
hitchhikers.”

Nielsen says
although specimens have only been spotted in the state since the beginning of
this year, “We’ve seen damage that indicates it’s been in Michigan for a
while.”

The first actual
Michigan sightings of this nasty critter occurred in Eaton and Berrien counties
in the southwest portion of the state in January 2011. In March, additional
stink bugs were found in Ingham and Genesee counties. Michigan State University
entomologists, however, predict the stink bug population will spread widely
throughout the Great Lakes region over the next few years.

Significant Agricultural Threat

In her study,
“Invasive Forest Pests: Trend and Impacts,” Dr. Deborah G. McCullough of MSU’s
departments of entomology and forestry, wrote: “More than 450 non-native insect
species that feed on forest trees are established in the United States, and the
accumulation rate was relatively steady between 1860 and 2006. Slightly less
than 15 percent of the insect species … have caused reportable damage. Sap
feeding insects such as scales, aphids, and adelgids dominated the complete
list of non-native insects, while foliage feeders were most abundant in the
list of damaging pests.”

Nielsen says the
BMSB is native to semi-tropical climates, but adds the bugs’ “over-winter
survivalist behavior allows them to survive in Michigan.”

The BMSB rides
out the winter by hunkering down in houses, where it presents no health or
property damage issues. “The best method for controlling BMSB indoors is by
sealing entry points like cracks around window and door trim, exhaust vents,
air conditioners, ceiling fixtures,” said Holton. “Once they’ve gained entry,
vacuuming live and dead bugs is the best option. Pesticide treatments are not
recommended because they will not prevent additional invasions,” she said.

While
acknowledging the presence of bugs in a person’s home might be annoying, Dr.
Chris DiFonzo, a field crops entomologist at MSU, and Nielsen agree the real
threat stink bugs pose is the damage they can do to Michigan agriculture.

Holton emphasizes
that BMSB is unlike the emerald ash borer and Dutch elm disease, which
decimated millions of Michigan trees. The ash borer insect and elm disease
attacked and killed trees, she notes, but BMSB “attacks the fruit of the plant
or tree and not the tree itself.” “However, it will be a very serious pest for
producers of agricultural crops and nurseries.”

BMSBs feed on
fruit fluids by puncturing the plants’ tissues with their stylet — the
needle-sharp extension the bug uses to break through the fruit’s surface. This
puncturing and sucking process produces dimples, deformities or scars, known as
“cat-facing,” on the fruit’s skin and can make the product unmarketable.

Nielsen
places stink bug damage to tree fruit in the Mid-Atlantic States in the $37
million range, but emphasizes that the greater diversity of crops in Michigan
poses a much greater risk.

“BMSB has a very
wide host range unlike many pests which only feed on specific plant material,”
said Holton. “Because of its wide host range and the damage resulting from its
feeding, BMSB has the potential to have a great impact on agricultural crops,
particularly those that are not normally treated for insect pests during the
growing season.”

Holton says the BMSB
could be “devastating for a variety of fruits, vegetables, field crops and
ornamental plants. Potentially impacted crops in Michigan include apples, peaches,
corn, cherries and others,” she said. “It has also been reported on many
ornamental plants, weeds, soybeans and beans for human consumption.”

Detection and Elimination

Ken Nye, Michigan
Farm Bureau spokesman, says his organization has been taking an active role
with MSU researchers and the Michigan Department of Agriculture and Rural
Development, as well as with the U.S. Department of Agriculture.

“We’ve been
working with MSU’s farm extension program to disseminate information to
growers,” Nye said. “The perception is that a large number of farm commodities
are threatened by damage by the stink bug.”

Nye added: “We are
letting growers know what control methods are going to work, and the many
different resources we’re bringing to bear — from biological controls growers
can utilize to monitoring weather patterns that might help us determine a
scientifically timed process based on the bug’s growth cycle and at what point
the bug can be dealt with most effectively.”

Holton says early
detection and rapid response programs are “crucial for dealing successfully
with exotic pests which threaten the state’s agricultural interests and impact
our natural resources and environment.”

She adds that
while detection of BMSB is not good news, “the fact that it’s been detected
early provides us the opportunity for outreach to the affected communities and
to dial-up control strategy recommendations — including applying for emergency
use pesticide registrations, if necessary.”

Holton also said
the department will be working in concert with MSU to “identify possible
controls for both agricultural and home use,” she said. “For ag-based use,
other states such as Maryland and Pennsylvania have had some success with
pyrethrum-based compounds.”

Nielsen said the
best defense against the BMSB is to slow it from spreading. “We’re working out
a rapid response protocol that will use USDA-approved insecticides as well as
control and monitoring techniques.”

The good news,
according to Nielsen, is that agricultural pesticides already in use have
proven effective in trials conducted by MSU, and controlling or eradicating the
pest won’t require entirely new chemical compounds.

DiFonzo also says
the BMSB population can be managed using what she calls “off-the-shelf”
agricultural chemicals.

If that’s the case,
perhaps Michigan can remove the stink bug threat and enjoy the sweet smell
of success.